@ShareYourKnowledge We don't review hypothetical code, only the real thing.

My first reaction to the second comment was that even if the comment was asking a question about hypothetical code, it was a comment. It's not a real question of this site, so I don't mind people asking question about hypothetical situation since it's only a comment in response to answer.

Can a question in a comment really be off-topic ?

Is this a problem for this site if user ask questions about hypothetical situation in response in an answer ?

The problem that arise from that discussion is an argumentation about what is on/off topic for the site which was more damaging in my eyes than asking an hypothetical question.

If a comment is really off-topic, should we not flag it instead ? Comments are second citizen so if they are a nuisance we should get rid of it.

\$\begingroup\$I don't know if "off-topic" is the way I would characterize the comment. I think that the original poster was trying to seek clarification, but it ended up being closer to an unreasonably broad follow-up question instead.\$\endgroup\$
– 200_successApr 13 '16 at 17:59

1

\$\begingroup\$Sorry, that was bad phrasing from me. It sounded like the OP was about to ask another question, so I was trying to warn them ahead of time that the question they were asking was off-topic, and I failed.\$\endgroup\$
– Nic HartleyApr 14 '16 at 2:34

\$\begingroup\$@QPaysTaxes I understand what you were trying to achieve and this is why I asked this question. I was trying to see if it was legitimate or not and see what action should I take if it happens again.\$\endgroup\$
– Marc-AndreApr 14 '16 at 12:59

Comments are not questions. In principle they cannot be off-topic for the site (since they're not questions, right?)

But Comments can be other things. Among these is "too chatty".
A comment like this invites extensive discussion in a way. As such it's not a good comment. It would be helpful to refer the participants to chat where they can have a proper discussion.

\$\begingroup\$I like the option to propose a chat if I see something similar in the future.\$\endgroup\$
– Marc-AndreApr 13 '16 at 18:02

\$\begingroup\$Speaking of birds, did you know that the Great Blue Heron is only related to the Little Blue Heron at Class level? That is to say they are both "birds" rather than even being in the same family?\$\endgroup\$
– RaystafarianApr 14 '16 at 13:45

If you want to answer it, feel free to do so. However, do note comments aren't supposed to last forever. Questions posed there are likely to only benefit the OP, not to the rest of the visitors.

Don't feel obligated to even reply to such comments with an answer. Explaining comments aren't supposed to be used for questions is a valid response. However, comments can't be off-topic. They can be 'too chatty'. They can be 'not constructive'. But technically there's no such thing as on-topicness for comments.

Comments are supposed to be used for clarification. Request for clarification, suggested clarifications, etc.

Comments are not supposed to be used for questions. However, questions posed in the comments can provide context and/or clarification about the intent of the author.

Is this a problem for this site if user ask questions about hypothetical situation in response in an answer?

No. It could be unwanted, it could even be noise, but it's not a problem.